Techniques and Facilities for Microwave Radar Testing

HAT radars are marvels of ingenuity has long since become common knowledge. This ingenuity is reflected, however, in complexity of circuits. A rough index of this is found in the number of vacuum tubes, which for a single radar may range from 50 to 250. Notwithstanding the most careful design, it is easy for the radar performance to become impaired under operating conditions. Not only is radar complex, but its performance criteria are less tangible than those of conventional communication systems. Ordinary radio is to some extent self-testing in that reception of intelligible speech or signals frequently constitutes a sufficient check of satisfactory performance. With radar, the greater the range coverage and the more accurate the data, the more valuable the information is likely to be. However, the working range may fall to a fraction of the possible maximum or some other degradation or malfunctioning may occur, with nothing in the operation of the radar to tell that this has happened. Since lack of maximum performance may have serious military results, measurement of performance assumes the utmost importance in radar work. The new techniques and new frequency ranges employed for radar necessitated the wartime development of a wide variety of new types of test equipment. A large part of this development work was concentrated at Bell Laboratories and at the N.D.R.C.'s Radiation Laboratory at M.I.T., working in close coordination with one another and with the technical services of the Army and Navy.